8 inch drives ?
Dave Baldwin
I've seen a couple of posts about 8 inch drives being unreliable. That
hasn't been my experience, so I'm wondering why some people are saying
that.
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Ramon Gandia
Dave Baldwin wrote:
>
> I've seen a couple of posts about 8 inch drives being unreliable. That
> hasn't been my experience, so I'm wondering why some people are saying
> that.
Well, in 1980-81 I had this CCS-300 machine with dual Siemens
drives. None ever lasted more than 4 - 6 months, and it was
light duty use. I eventually went to Shugarts, and they went
a lot longer, like 8-9 months. Alltogether I think I went thru
a dozen drives, and they were expensive in those days. But it
cost even more to send them in for repair....
They were used in double density, maybe that had something to do
with it. I imagine Single Density are pretty reliable.
The Altair (Pertec) drives never gave me any problem, but it is
hard to get good ones. All I ever had to do was align them and
presto.
But those were hard sectored, and not really cp/m compatible, although
I used the Lifeboat cp/m 1.4 for the Altair. Which I still have,
although I removed the Altair boot Prom some time ago. My next
few 2716's (on the 64 K memory card ) had my own monitor, and boot
code for the Altair disk or the 5.25 double sided double density
from Fulcrum. In later years I took out the Altair boot code,
although I didn't erase anything, just saved the 2716's, they are
cheap.
My 5.25 drives have been solid, but not so the floppies. Seems like
they get eaten with regularity, whereas the 8" floppies are much
better. Its the drives that gave me fits.
I really like the new 3.5 1.44 mb drives, they are a bit slow, but
the floppies seem bulletproof and the drives themselves never damage
the floppy data if the power is turned off with a drive in it. Also
very easy to power. I wrote a BIOS using 128 byte double density
sectors, 77 tracks and 26 sectors per side, single sided, which
you will recognize as an almost copy of standard cp/m disk, except
for writing double density. Works fine. Its what I use on the
Altair now, but I can still boot the Fulcrum unit.
Apparently your luck with 8" drives has been better! Tell us your
experiences. Tis all we do nowadays, reminisce.....
Ramon, AL7X, Nome, Alaska.
A.R. Duell
Ramon Gandia <r...@nome.net> writes:
>Dave Baldwin wrote:
>>
>> I've seen a couple of posts about 8 inch drives being unreliable. That
>> hasn't been my experience, so I'm wondering why some people are saying
>> that.
>Well, in 1980-81 I had this CCS-300 machine with dual Siemens
>drives. None ever lasted more than 4 - 6 months, and it was
>light duty use. I eventually went to Shugarts, and they went
>a lot longer, like 8-9 months. Alltogether I think I went thru
>a dozen drives, and they were expensive in those days. But it
>cost even more to send them in for repair....
Hmm.... If a Shugart is only lasting you 9 months in _light duty_ use,
then either you were using them in a very rough environment, or there was
something else wrong (like high voltage glitches on the PSU). I've
_never_ had a Shugart 8" drive fail, and I've running a lot that are > 10
_years_ old.
Of course I do perform preventive maintenance on them. I do clean the
head assembly (no matter what the service manual says), I do lubricate
them, I do check the PSU, etc.
>My 5.25 drives have been solid, but not so the floppies. Seems like
>they get eaten with regularity, whereas the 8" floppies are much
>better. Its the drives that gave me fits.
I've never had an unrecoverable 8" disk error either. Now, these darn
modern 3.5" things...
>I really like the new 3.5 1.44 mb drives, they are a bit slow, but
>the floppies seem bulletproof and the drives themselves never damage
>the floppy data if the power is turned off with a drive in it. Also
>very easy to power. I wrote a BIOS using 128 byte double density
>sectors, 77 tracks and 26 sectors per side, single sided, which
>you will recognize as an almost copy of standard cp/m disk, except
>for writing double density. Works fine. Its what I use on the
>Altair now, but I can still boot the Fulcrum unit.
I'll disagree with that. I've had no end of problems with 3.5" disks,
particularly the 1.44Mbyte ones. On one classic occasion, I copied some
files onto a disk, made a backup on another disk from the same box, kept
one in my desk (with some other disks), and carried the other one in my
bag. 1 month later, when I needed the files again, _both_ were
unreadable. It took most of the night to recover them.
And have you ever tried aligning a 3.5" drive? It's a right pain, even
with the service manual. 8" drives are a lot easier. And don't assume a
brand new 3.5" drive is correctly aligned - I've met plenty that are not.
>Apparently your luck with 8" drives has been better! Tell us your
>experiences. Tis all we do nowadays, reminisce.....
>Ramon, AL7X, Nome, Alaska.
--
-tony
ar...@eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
Dave Baldwin
In article <52r09j$4...@lyra.csx.cam.ac.uk> you wrote:
: Ramon Gandia <r...@nome.net> writes:
: >Well, in 1980-81 I had this CCS-300 machine with dual Siemens
: >drives. None ever lasted more than 4 - 6 months, and it was
: >light duty use. I eventually went to Shugarts, and they went
: >a lot longer, like 8-9 months. Alltogether I think I went thru
: >a dozen drives, and they were expensive in those days. But it
: >cost even more to send them in for repair....
: Hmm.... If a Shugart is only lasting you 9 months in _light duty_ use,
: then either you were using them in a very rough environment, or there was
: something else wrong (like high voltage glitches on the PSU). I've
: _never_ had a Shugart 8" drive fail, and I've running a lot that are > 10
: _years_ old.
I've had few problems with any kind of floppy drives. I have a pair of
Shugart 801's that were installed new in 1981 that are still running and a
pair of Tandon 848-2's that I've been using since 1982. I have worn out a
number of boot disks over the years. My biggest problem is on the BBS
where I almost never use the floppies. I have to make sure and clean the
dust off them before I use them.
Allison
dib...@netcom.com (Dave Baldwin) wrote:
>I've seen a couple of posts about 8 inch drives being unreliable. That
>hasn't been my experience, so I'm wondering why some people are saying
>that.
David,
My experience is SA800 are nearly indestructable save for the head
load felt button. The latter SA850 two sided drive tended to bite the
media when the heads loaded reducing media life, I modified it to load
once media was inserted and the door closed, and get excellent
results. Microplous drives the plastic centering hubs used to break
after about two years, sooner if the cab was very warm. CDC drives
were ok, save for being noisy. Siemens drives worked well for me
never had trouble. I found used pertec drive to be poor as they were
cranky on alignment and tended to cook logic cards. I also had
several NEC two sided drives and these had a dashpot for soft head
load, excellent drives.
On my own system I've had the same SA800 for umteen years and junked
it for motor bearings. I did that as I had a new in the box spare and
it was easier. No complaints as the first drive was used when I got
it 18 years ago!
Minifloppies <5.25"> Shugart SA400/400/450 were all junk in my book.
The single sided two disk one positioner/spindle DEC RX50 was pretty
poor to. Very noisy and alignment tended to drift if in a warm box!
I used teac full heights that were solid.
In the half heights Toshiba, fujitsu, teac, mitsubishi and MPI all
good, some nicer door locks and such but, all of the ones I have are
old and good. The teac FD55 series are very good as they do both
300/360 and 720/780k/1.2m reliably.
In the 3.5" format Sony, teac, toshiba all good. Never had any
trouble with any of them save for one damged head at work...
user put a disk in upside down and then pulled it out with pliers.
It ripped the head off it's mount. Can't blame the drive for that!
Over the years I've been moving the systems from 8" to 5.25 and then
3.5" for media standardization. While I can still do the larger I do
so rarely and am considering dropping 8" entirely and limiting 5.25
to one drive on the s100 crate for compatability with old kaypros and
the like. Reason, 3.5 inch drive detect power fail and do not write
on the media it's left in the drive. The 5.25 and 8" drives will
write garbage if media is in them on power down. I've munged a lot of
media by trashing the data because I forgot to open th door or eject
the media.
Allison
Real address is: Allisonp @ WORLD dot STD dot COM
This was done to discourage some of the junkmailers.
Dave Baldwin
Thanks for the info. By the way, if you really want to throw the junk
mailers off, you need to put a bogus reply address in your header.
A.R. Duell
Alli...@world.std.com (Allison) writes:
>Minifloppies <5.25"> Shugart SA400/400/450 were all junk in my book.
Which were those infernal drives with the flat plastic disk with a spiral
groove as a head positioner? Those things couldn't hold alignment for 5
minutes (OK, I exagerated, but only just). Apple used the mechanical
side for the Disk ][, alas...
>The single sided two disk one positioner/spindle DEC RX50 was pretty
>poor to. Very noisy and alignment tended to drift if in a warm box!
>I used teac full heights that were solid.
I've had _some_ success with full-height Tandons (like the original IBM
PC drives) provided they're set up correctly.
> In the half heights Toshiba, fujitsu, teac, mitsubishi and MPI all
>good, some nicer door locks and such but, all of the ones I have are
>old and good. The teac FD55 series are very good as they do both
>300/360 and 720/780k/1.2m reliably.
Be warned. The name 'FD55' covers at least 4 totally different drives. I
have service manuals for 2 of them, and schematics for another, and I've
worked on yet another...
Over the years they've become cheaper to produce (the electronics is now
1 large ASIC and a stepper motor driver), and IMHO less well built, and a
lot harder to repair. On the latest ones you need an alignment disk to
refit the main PCB - the track 0 sensor is on the PCB, and the PCB has
slotted mounting holes. A right pain if you need to replace any components.
Oh, and another useful fact, the suffix letter (I think it's the _first_
suffix letter) gives the drive type, as follows
A - 40 track SS
B - 40 track DS (i.e. PC 360K)
E - 80 track SS (Does this exist - I've seen a mention of it in the manual)
F - 80 track DS (would be 720K on a PC)
G - 80 track DS, 360 rpm (1.2Mbyte on a PC)
I _think_ some Teac 3.5" drives have an H suffix. This either fits the
pattern above and indicates 1.44Mbyte, or simply stands for High Density.
From the above pattern, it appears that C and D should be the single and
double sided versions for some other number of tracks (77???). Does
anyone know for sure?
>In the 3.5" format Sony, teac, toshiba all good. Never had any
>trouble with any of them save for one damged head at work...
>user put a disk in upside down and then pulled it out with pliers.
>It ripped the head off it's mount. Can't blame the drive for that!
I've had more problems with 3.5" disks than any other type (and I
currently run 8", 5.25", 3.5", 3" drives and a number of demountable hard
disks). Among the more classic problems are the time the eject latch
failed and the drive attempted to eject the disk with the top head still
loaded (Ouch!), and the countless times the metal shutter on the disk has
sprung apart and caught on the spindle during ejection. This generally
requires a partial strip-down of the drive to sort out.
>Over the years I've been moving the systems from 8" to 5.25 and then
>3.5" for media standardization. While I can still do the larger I do
>so rarely and am considering dropping 8" entirely and limiting 5.25
I'm going the other way. I have a 5.25" drive on my classic PERQ
(switchable in place of the standard 8") simply because the disks are a
lot easier to obtain, and sufficiently reliable for transfering data to
the PC in the next room. The only reasons I have a 3.5" drive on my PC
are that (a) a lot of software comes on 3.5" disks and (b) most PCs at
work only have 3.5" drives. I rarely trust it for backups that I care
about...
>Allison
Ramon Gandia
A.R. Duell wrote:
> I'll disagree with that. I've had no end of problems with 3.5" disks,
> particularly the 1.44Mbyte ones. On one classic occasion, I copied some
> files onto a disk, made a backup on another disk from the same box, kept
> one in my desk (with some other disks), and carried the other one in my
> bag. 1 month later, when I needed the files again, _both_ were
> unreadable. It took most of the night to recover them.
Well, there are good brands of floppies out there, and some bad ones.
The most *notorious* bad ones are the infamouse A.O.L. disks. Those
read fine for the aol program. But if you format them (with verify)
you will in almost half the cases not be able to format it without
errors. Often, its the boot track that won't format.
The rest of the time the disk formats okay (or sometimes with some
hesitations), but finishes okay. Then you write your data on it,
and in a few reads it bombs out with the dreaded error message.
I am guessing that aol got some floppies that have a special magnetic
media that they record with a special recorder, which we can read from
okay (the aol program), but do not accept very well normal recording.
Since I standardized on fresh 3-M floppies I have had only two or
three that didn't format, and the rest have never lost me any data.
I buy my floppies in cases of 100, so I have had about 300 disks so
far without problems. In fact, I am ordering another 100. Good
brand. I am sure that quite a few of the other brands are very good
too.
On the 5 and 8 inch side, I had great luck with Dysan 8" disks, but
when they went to 5 inch and a larger production run, it all went
to pot. My 5" Dysans, in a lot of 100 had over 50 floppies go bad
so I threw out the rest. I think I used Maxell after that with no
problems attributable to the floppy itself. Last batch was 3-M, and
again no problems.
Perhaps you can share your experiences with disk brands.
Ramon, Nome, Alaska clear, sunny, 39F. Snow all gone.
bill_h
I believe Dysan's 8" disks were made by 3-M, for whatever that's worth
When it come to verifying drive function, there's absolutely NOTHING
that can beat using a DDD alignment disk, and looking at the
"sensitivity" test. Tells you tons of info about how well that
particular drive does at amplifying the signal......which, obviously,
is a major factor in 'drop-outs'
Then there's the matter of alignment....how else can you know what's
going on? Guess?
I have used Shugart 800's and 850/851's, but they're big and heavy
and take 110vac. Me and 110vac don't get along so good.
I went to Tandons, 848-1 and later 848-2's, but I considered them
too flimsy....they'd go out of alignment if the temperature changed
four degrees.....
I settled on Qume DT-8's, 1/2ht DS DD, and they've held up very well
Oh, I also had a Qume full height many years ago.....it was solid, too.
I think the prices asked by California Digital for their 8" drives
probably reflect the facts of life, in that the more expensive drives
are probably better one way or another.
I hated Wabash and EcType disks....many more errors than Dysan, CDC,
IBM, Verbatim, 3M, in my experience. On the other hand, living in
3-M's back yard, I was told 3-M supplied in slurry form the coatings
used by all but a very small number of manufacturers.....I think
Memorex was one non-3-M one....
j.r. pierce [see .sig]
Alli...@world.std.com (Allison) wrote:
>Newsgroups: comp.os.cpm
>Path: news.scruz.net!kithrup.com!news.Stanford.EDU!nntp-hub2.barrnet.net!cam-news-hub1.bbnplanet.com!howland.erols.net!newsfeed.internetmci.com!news.sprintlink.net!news-peer.sprintlink.net!news.mathworks.com!uunet!in3.uu.net!world!news
>From: Alli...@world.std.com (Allison)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Um, THAT is the field that the spam trollers strip for junk mail...
>Subject: Re: 8 inch drives ?
>Sender: ne...@world.std.com (Mr Usenet Himself)
^^^^^^^^^^^^^^^^^^^^^^^^^^
They might look at this one too, but I believe normally this is left
blank (or 'default').
>Message-ID: <DyLuK...@world.std.com>
>Date: Tue, 1 Oct 1996 16:13:45 GMT
>References: <dibaldDy...@netcom.com>
>Nntp-Posting-Host: world.std.com
>Organization: The World @ Software Tool & Die
>X-Newsreader: Forte Free Agent 1.0.82
>Lines: 55
..
>Allison
>Real address is: Allisonp @ WORLD dot STD dot COM
> This was done to discourage some of the junkmailers.
You'd better work on it!
--------------------------------------------------------------------
This posting has a invalid email address to discourage bulk emailers
if you need to mail me try "pierce at scruznet dot com"
--------------------------------------------------------------------
Allison
ar...@eng.cam.ac.uk (A.R. Duell) wrote:
>Be warned. The name 'FD55' covers at least 4 totally different drives. I
>have service manuals for 2 of them, and schematics for another, and I've
>worked on yet another...
>Over the years they've become cheaper to produce (the electronics is now
>1 large ASIC and a stepper motor driver), and IMHO less well built, and a
>lot harder to repair. On the latest ones you need an alignment disk to
>refit the main PCB - the track 0 sensor is on the PCB, and the PCB has
>slotted mounting holes. A right pain if you need to replace any components.
The ones I have are four varients of the fd55FGV aka RX33 that does
all 80track DS formats. They are all interchagable and have different
PC cards, jumpers and door latch mechanisms. I generally use them
for 1.2m PC or 780k CP/M.
Don Maslin
Ramon Gandia (r...@nome.net) wrote:
: Dave Baldwin wrote:
: >
: > I've seen a couple of posts about 8 inch drives being unreliable. That
: > hasn't been my experience, so I'm wondering why some people are saying
: > that.
I have to agree with Dave on this. My experience with 8 inchers -
largely Shugarts - has been really quite excellent. I have a few
kicking around here that have to be pushing 20 years old and still
function well.
: Well, in 1980-81 I had this CCS-300 machine with dual Siemens
: drives. None ever lasted more than 4 - 6 months, and it was
: light duty use. I eventually went to Shugarts, and they went
: a lot longer, like 8-9 months. Alltogether I think I went thru
: a dozen drives, and they were expensive in those days. But it
: cost even more to send them in for repair....
: They were used in double density, maybe that had something to do
: with it. I imagine Single Density are pretty reliable.
: The Altair (Pertec) drives never gave me any problem, but it is
: hard to get good ones. All I ever had to do was align them and
: presto.
: But those were hard sectored, and not really cp/m compatible, although
: I used the Lifeboat cp/m 1.4 for the Altair. Which I still have,
: although I removed the Altair boot Prom some time ago. My next
: few 2716's (on the 64 K memory card ) had my own monitor, and boot
: code for the Altair disk or the 5.25 double sided double density
: from Fulcrum. In later years I took out the Altair boot code,
: although I didn't erase anything, just saved the 2716's, they are
: cheap.
: My 5.25 drives have been solid, but not so the floppies. Seems like
: they get eaten with regularity, whereas the 8" floppies are much
: better. Its the drives that gave me fits.
Yes, most of the 8" floppies were quite durable, though I have had
experience with the magnetic material sluffing off of old ones.
Almost always in the directory area, of course!
: I really like the new 3.5 1.44 mb drives, they are a bit slow, but
: the floppies seem bulletproof and the drives themselves never damage
: the floppy data if the power is turned off with a drive in it. Also
: very easy to power. I wrote a BIOS using 128 byte double density
: sectors, 77 tracks and 26 sectors per side, single sided, which
: you will recognize as an almost copy of standard cp/m disk, except
: for writing double density. Works fine. Its what I use on the
: Altair now, but I can still boot the Fulcrum unit.
Sounds a lot like the old Altos and Sierra 8" DD format. Just don't
try to read it with a 765, though.
: Apparently your luck with 8" drives has been better! Tell us your
: experiences. Tis all we do nowadays, reminisce.....
: Ramon, AL7X, Nome, Alaska.
- don
do...@cts.com
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A.R. Duell
Ramon Gandia <r...@nome.net> writes:
>A.R. Duell wrote:
[floppies]
>Well, there are good brands of floppies out there, and some bad ones.
>The most *notorious* bad ones are the infamouse A.O.L. disks. Those
>read fine for the aol program. But if you format them (with verify)
>you will in almost half the cases not be able to format it without
>errors. Often, its the boot track that won't format.
I refuse to ever re-use cover disks, free disks, or whatever. My data is
simply too valuable to trust to unknown media. The one thing such disks
do get used for is a true scratch disk for testing the mechanical
operation of a newly-repaired floppy drive.
>Since I standardized on fresh 3-M floppies I have had only two or
>three that didn't format, and the rest have never lost me any data.
>I buy my floppies in cases of 100, so I have had about 300 disks so
>far without problems. In fact, I am ordering another 100. Good
>brand. I am sure that quite a few of the other brands are very good
>too.
>On the 5 and 8 inch side, I had great luck with Dysan 8" disks, but
>when they went to 5 inch and a larger production run, it all went
>to pot. My 5" Dysans, in a lot of 100 had over 50 floppies go bad
>so I threw out the rest. I think I used Maxell after that with no
>problems attributable to the floppy itself. Last batch was 3-M, and
>again no problems.
>Perhaps you can share your experiences with disk brands.
I've had a lot of luck with 3M disks as well - in fact that's what I tend
to buy. Unfortunately, I am told that 3M are moving out of the magnetic
media business, so such disks might not be arround much longer.
Inmac +80's seem good as well - I've never had any problems with them
_Old_ Dysan are good - 8" and 5.25". But it was a Dysan 3.5" that caused
me all the trouble I mentioned earlier, so I no longer buy them.
There've been other brands that used to be good (amazingly, Tandy/Radio
Shack were amongst them), but which are now, alas useless.
Am I the only person who thinks that most floppies are too _cheap_ ? I'd
gladly spend $20 or more on _1 disk_ if I knew it would not loose my data.
>Ramon, Nome, Alaska clear, sunny, 39F. Snow all gone.
Will Rose
A.R. Duell (ar...@eng.cam.ac.uk) wrote:
[...]
: Oh, and another useful fact, the suffix letter (I think it's the _first_
: A - 40 track SS
: B - 40 track DS (i.e. PC 360K)
: E - 80 track SS (Does this exist - I've seen a mention of it in the manual)
: F - 80 track DS (would be 720K on a PC)
: G - 80 track DS, 360 rpm (1.2Mbyte on a PC)
: I _think_ some Teac 3.5" drives have an H suffix. This either fits the
: pattern above and indicates 1.44Mbyte, or simply stands for High Density.
There are several sorts of 235H drives, and I don't have the docs
for them, but the one I have is a 1.44, and a 235J is a 2.88.
A.R. Duell
c...@cts.com (Will Rose) writes:
The FD235-HFR (I think that's the number) is a switchable 1.44M/720K
drive which would seem to indicate that the H suffix means 1.44M.
I suspect I was never used, and J, indeed, is 2.88Mbytes.
>Will
>c...@crash.cts.com
j.r. pierce [see .sig]
bill_h <bil...@azstarnet.com> wrote:
>I believe Dysan's 8" disks were made by 3-M, for whatever that's worth
The ORIGINAL 8" Dysan disks were made by Dysan. They had their own
media coating and polishing plant, their own jacket stamps, etc. This
is circa 1977. They went to pot sometime around 1980. DRI used to
use dysan disks exclusively back then until the quality went downhill.
>
>I have used Shugart 800's and 850/851's, but they're big and heavy
>and take 110vac. Me and 110vac don't get along so good.
800/801's were built like a tank. Lasted forever if they didn't get
seriously abused. The double sided ones had problems early on but got
better.
>I went to Tandons, 848-1 and later 848-2's, but I considered them
>too flimsy....they'd go out of alignment if the temperature changed
>four degrees.....
Tandon ANYTHING were troublesome. The original IBM PC had Tandon
5.25" drives that were horrible.
>I settled on Qume DT-8's, 1/2ht DS DD, and they've held up very well
Qume made a good DSDD drive, yeah. Expensive tho.
>Oh, I also had a Qume full height many years ago.....it was solid, too.
Ah, thats the one I remember.
CDC 8" drives were a nightmare to realign but stayed solid for years
of use (the original Intel MDS-800 used a pair of these).
The most troublesome 8" drives had to be the dual Persci's with the
voice-coil mechanism. When they worked, they were great (i.e. fast
seeking), but when they were bad they were horrid.. Hardly anyone
could align them and tune the servo mechanism correctly, a friend of
mine and I finally mastered this, but it was no fun.
-jrp
Ramon Gandia
A.R. Duell wrote:
> _Old_ Dysan are good - 8" and 5.25". But it was a Dysan 3.5" that caused
> me all the trouble I mentioned earlier, so I no longer buy them.
>
> There've been other brands that used to be good (amazingly, Tandy/Radio
> Shack were amongst them), but which are now, alas useless.
>
> Am I the only person who thinks that most floppies are too _cheap_ ? I'd
> gladly spend $20 or more on _1 disk_ if I knew it would not loose my data.
Well, looking back I had a very few old 5" Dysans, and they were okay.
My problems started when they went to the new overseas factory. All
my old 8's and less than half a dozen 5" were old production run. OK.
The rest of the 5" (case of 100) was the new run and was mostly bad.
The jacket also seems to be flimsier. I don't like flimsy jackets
because when the disks are laying about they can get damaged by laying
something heavy on it. Yes, yes, its careless, but sometimes the disk
is under a piece of paper and I can't see it in time!
Too bad about 3M. Verbatim 8" and 5" have the flimsy jacket. I think
Maxells are good.
Also I did have a couple of boxes of the Inmac 8" hard sectored for
the Altair, and true enough, they were good.
But in the future I am staying with 3.5" drives due to the fact they
don't eat data if you turn the computer off or on with a disk in the
drive. This alone is an endearing quality. It eliminates the chances
of "pilot error".
As for the $20 floppy, well, I think its coming. Sony and Compaq
have put out now a new 3.5 inch drive that reads and writes regular
1.44 mb disks, but also can take a special Sony floppy, sort of
a Bernouli thing, and it holds about 180 or 200 megabytes. This drive
will cost about $150 - $200 retail and sure looks very promising.
It does not state in the literature if it uses the floppy controller,
the IDE, Scsi or propietary, and if it takes a special driver or BIOS
support.
Time to find out.
Ramon, AL7X, Nome, Alaska
Ramon Gandia
Don Maslin wrote:
Ramon Gandia wrote:
> : I really like the new 3.5 1.44 mb drives, they are a bit slow, but
> : the floppies seem bulletproof and the drives themselves never damage
> : the floppy data if the power is turned off with a drive in it. Also
> : very easy to power. I wrote a BIOS using 128 byte double density
> : sectors, 77 tracks and 26 sectors per side, single sided, which
> : you will recognize as an almost copy of standard cp/m disk, except
> : for writing double density. Works fine. Its what I use on the
> : Altair now, but I can still boot the Fulcrum unit.
>
> Sounds a lot like the old Altos and Sierra 8" DD format. Just don't
> try to read it with a 765, though.
>
No problem with the 765. In fact, since I did not write a FORMAT
program for the 128 byte sector double density pattern, I just
formatted them with 22-Disk on my PC and used them on the Altair
(that has the 1797 WD controller).
I started a long lasting thread in Compuserve about the 765/179x
controllers, as a lot of my CP/M disks would not read on 22 Disk.
What I found out from Sydex's (22-Disk author) Miriam St.Clair, is
that the 765 goes to sleep for a while after the index hole is
sensed. When it wakes up it is supposed to still be reading the
post-index gap. This works fine in floppies formatted and used by
the 765, because it has a "Format Track" command sequence, and does
not require the track pattern, including i.d., sector numbers and
gaps to be written out in the Format program.
The 179x does not have a Format Track command, but has a Write Track
command. To format, you write the blank track date, gaps, id's, etc
in your Format.Com program, and then play it back into the drive
with Write Track activated. Presto, the track is formatted.
Again, no problems with the 765 and the 1797 reading each other,
provided the track is laid out in accordance with the IBM spec, which
has a long enough post-index gap field. I think this is mostly 4Eh,
for something like 80 bytes or more, then the I.D. field starts.
However, in the 1980's, disk space was getting to be hard to find,
and a lot of floppies were jammed with 400K, 420K or more per side,
and they did this by reducing the gap fields to minimum and crammed
more sectors into the track that way. This could be done on the
1797 WD chip, just write out a new pattern on the Format.Com program.
The 765 does not work this way, and the gap fields and intersector
fields are all pre-programmed into the chip with only the
Format Command issued (after setting up the proper track under the
head).
Thus, many such CP/M disks will not read on the 765, because the
first sector after the index is missed. When the 765 wakes up
it finds itself already past the sector i.d., so what it finds is
considered garbage and ignored. You can confirm this using ANADISK
and see for yourself that sector #1 is missing in Most tracks, although
once in a while one will come in at random, depending on how tight
the timing. Some 765 nap a bit less and the controller will work,
others won't.
This was talked about in the 1980's, and it was called a "bug" in
the 765, since the 1797 series was considered "standard". Along
comes IBM and puts the 765 in their PC, and after a few years it
became the de-facto standard, so now people consider the 1797 series
to be the one with the "bug" in that it can write unreadable (to the
765) controller. Sheesh!
The solution is to FORMAT the floppy on a 765 and then either controller
chip can read and write the data to disk. On seriously jam packed
floppies the last sector may overlap the index hole and the disk
will not format under the 765. I have not encountered this problem
YET on my disks, but no doubt many of you have.
If your Format.Com program and disk parameters are not too jam packed,
you could edit the Format.Com program to put in more post-index
bytes before the first sector i.d. field and this will fix the problem
again. But the usual case is you have an archive of cp/m disks
already written, and you find that the 765 PC controller will not
be able to handle.
As for 128 byte double density sectors, the 765 supports this; it
is the PC that does not allow you to use it, and the BIOS only
supports 256 bytes and up for sectors. However, I have found that
using 22-Disk, the BIOS is bypassed (smart of Sydex) and it is
possible to read the 128 byte sector disks with 22-Disk, 22-Nice
CP/M emulator, and ANADISK. I would not want to bet this is the
case with other disk programs.
Check it out: 128 byte DD sectors are ok on the (IBM 5740?) 5-inch
specifications and it is listed in the 765 documentation as being
supported.
As an aside, the 765 supports floppies with powers of 128 byte
sectors, like 128, 256, 512, 1024, 2048 etc. Where the 1797 series
will support any multiple of 128. There have been some CP/M
computers that read and write one-sector floppies where the sector
occupies the entire track and comes out to an oddball multiple of
128 bytes.
Lastly, Sydex and Miriam St. Clair were wonderful. When I reported
that Anadisk would not see the first sector, they modified the
program so Anadisk reads in the whole track, index gaps and
intersector gaps, and then it is possible to see things. But they
could not fix 22-Disk, so sector 1 is still invisible there as it
reads by the sector, not by the whole track. The new version of
Anadisk has been out about 16 months out thanks to my urging and
Miriam St. Clair. If you do not have this version, be sure to
download it.
Sydex is a super company. They make PC software now, but they DO
understand and support their CP/M stuff, and continue to support
their cp/m or emulator programs. Their staff is well versed in
cp/m and cp/m disk formats and file system. It is refreshing to
talk (or e-mail) with someone intelligent. Not like at Microsoft
tech support where the term "intelligent" and "tech support" are
an oxymoron!!
Ramon, Nome, Alaska
Ramon Gandia
j.r. pierce [see .sig] wrote:
>
> Alli...@world.std.com (Allison) wrote:
>
> >Newsgroups: comp.os.cpm
> >Path: news.scruz.net!kithrup.com!news.Stanford.EDU!nntp-hub2.barrnet.net!cam-news-hub1.bbnplanet.com!howland.erols.net!newsfeed.internetmci.com!news.sprintlink.net!news-peer.sprintlink.net!news.mathworks.com!uunet!in3.uu.net!world!news
> >From: Alli...@world.std.com (Allison)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> Um, THAT is the field that the spam trollers strip for junk mail...
>
> >Subject: Re: 8 inch drives ?
> >Sender: ne...@world.std.com (Mr Usenet Himself)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^
>
JR and Allison.
Check out my headers, posted from Netscape in Windows 95 to my ISP
news.nome.net etc. The ISP uses Sun Sparc with Unix, but then,
Netscape is a direct internet client so the Unix shell at the
ISP is routed around.
I *think* I have it right. Great! Now I can post to
alt.bomb.the.white.house and alt.sex.rape.little.kids
and no one will know who I am!
Ramon rfg.at.nome.dot.net <----heh heh.
>
Ramon Gandia <rfg.at.no...@to.keep.spam.out> wrote:
>This was talked about in the 1980's, and it was called a "bug" in
>the 765, since the 1797 series was considered "standard". Along
>comes IBM and puts the 765 in their PC, and after a few years it
>became the de-facto standard, so now people consider the 1797 series
>to be the one with the "bug" in that it can write unreadable (to the
>765) controller. Sheesh!
Actually... as product support for that chip doing that time,....
There were two different 765s the original and 765A, the primary
different was the VCO gap for index. How much of a difference,
my jinglish data sheets say 1.8ms reduced to .6ms! Obviously you want
the 765A... Oh, intel made the 765 under license and they lagged a
year or so on the -A version.
Now there is something called ECMA/ISO format that coincidently
deletes GAP4a, Sync and Index addres mark. The part numbers were
7265 and 745.
Bugs, one was IBM compatable and the other was ECMA/ISO no bug
just real specifications. Now the 179x is different it doesn't know
from formats beyond the basic sector marking. While more flexible it
couldn't seek four drives at the same time and depended on far more
support parts to handle things like drive select and a wide range of
step rates. It's payback is it can read or write anything.
Different ways to do the same task.
Bet your glad you asked. Oh, the 7265 is fully interchangeable with
the 765 and does read those errant disks.
Ramon Gandia
All...@somewhere.com (Allison) wrote:
> Bet your glad you asked. Oh, the 7265 is fully interchangeable with
> the 765 and does read those errant disks.
Good to know, but most, if not all, my controllers have the 765
embedded in one of those surface mount chips with 168 or more pins.
:-(
Also, there is the National DP8473V, which is now appearing in a
lot of pc's, or embedded in the 168 pin chips.
Then, my Pentium motherboard has no DIP i.c.'s. Besides the Pentium,
it has about 4 or 5 of the big chips and that is it. And it misses
sector 1 too. :-(
Like I said, the solution is to format the floppy with the PC, either
its 765, 765A or the DP8473V or one of the imbedetures, and then
put the floppy in the CP/M machine and copy the files to it. Which
is the perfect solution for those that have original machine in it!
Double :-( :-(
Ramon, Nome, Alaska